Improve GPU compatibility, RDNA2 kernels and startup diagnostics

- Match render/compute adapters and gate RR models by GPU capabilities
- Add RDNA2 native texture kernels and fix FP16 rounding
- Harden model builds, cache validation and packaging
- Add startup tracing, timeouts, documentation and regression tests

scripts/runtime_build_id.sh

@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+set -euo pipefail
+cd -- "$(dirname -- "${BASH_SOURCE[0]}")/.."
+revision=$(git rev-parse --short HEAD 2>/dev/null || echo unknown)
+sources=$(sha256sum tools/*.h tools/d4r_nvngx_shim.cpp tools/d4r_vulkan_frontend.inl tools/wine_nvcuda_bridge.c \
+  engine/*.h engine/*.cpp engine/*.inc | sha256sum | cut -c1-16)
+printf '%s-%s\n' "$revision" "$sources"